Research progresses on engineering Streptomyces avermectiniusthrough biotechnology

Objective To describe the current research progresses achieved in engineering Streptomyces avermectinius through mutagenesis and recombinant DNA technology.Methods Based on the elucidation of the biochemistry and genetics of avermectin biosynthesis,as well as the complete determination of avermectin biosynthesis gene cluster and the entire genome of Streptomyces avermectinius,the paper deals with engineering Streptomyces avermectinius through biotechnology.These progresses include selective production of desired components by pathway engineering,enhancement of the yield of avermectin especially through cloning manipulating regulatory genes instead of the traditional methods,such as random mutagenesis,production of novel avermectin via mutational biosynthesis and the improvement of avermectin ferment.Results The selective production of avermectin has achieved excellent progress up to now.The mutational strains can produce only components B of avermectins,that oligomycin biosynthesis gene cluster and aveD gene has been deleted.Combinational biosythesis has been proved to be a new approach to generate novel avermectins derivatives.However,there is still a need for revealing the complex regulatory mechanism and so on.Conclusions The availability of Streptomyces avermectinius genome and accumulation of the complicated regulatory mechanism information in combination with the recent development of combinatorial biosynthesis should us to engineer Streptomyces avermectinius as a more efficient host for the production of important commercial drugs.